This invention relates to a socket for the use of an electric part, in which a cover is closed on a socket body so as to hold an electric part such as an IC and to maintain a contact relation.
Heretofore, there is known an IC socket, in which a presser cover is open- and closably connected to one end of a socket body through a pivotal hinge, and the presser cover is closed on the socket body and then a lock member mounted on the other end of the socket body is engaged with the other end of the presser cover, or a lock member mounted on the other end of the presser cover is engaged with the other end of the socket body, thereby holding the IC placed on the socket body. When the presser cover is closed on the socket body, IC leads are pushed down and urged against corresponding contacts on the socket body by a lead presser member mounted on the presser cover, thereby flexing the contacts against elasticity thereof in order to obtain a contact pressure by their reactions. An opening for discharging heat is formed in the presser cover at a location corresponding to an IC mounting portion (i.e., portion where the IC is placed).
The socket body and the presser cover, respectively, are formed of a separate integrally molded part of a synthetic resin material. The pivotal hinge comprises a metal shaft or the like, thrust into a knuckle joint integrally molded on one ends of the socket body and presser cover. The lead presser member comprises a pillow-like projection integrally formed on the presser cover in such a manner as to correspond to a row of the leads. Otherwise, a lead presser member having the pillow-like projection is formed as a separate part, and the same is disposed within the heat discharging opening and pivotably supported on a resin frame forming the opening.
This conventional IC socket has the following problem. That is, a push-up force is normally acted on the pressure cover by each of the contacts when the cover is closed on the socket body. Therefore, when the presser cover is subjected to a measurement test, etc. under the condition that the electric part is heated by, for example, the push-up force applied the presser cover, or under a high temperature, the cover is gradually warped during a repeated use thereof, by the push-up force and heat. Since the accuracy of the presser member becomes unreliable (that is, the presser member is subjected to error in accuracy), it becomes difficult to obtain a proper pushing pressure and a proper contact pressure for each of the IC leads.
It also has the problem that a socket of this type must be disposed as an article of consumption even if the socket body is still in a good condition for use, and therefore, the socket is very short in service life and thus uneconomical.